<template>
  <div>
    <h2>当前求和：{{num}}</h2>
    <select v-model.number="n">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
      <option value="4">4</option>
    </select>
    <button @click="increment">+</button>
    <button @click="decrement">-</button>
    <button @click="incrementOdd">当前求和为奇数再加</button>
    <button @click="incrementWait">等一等再加</button>
  </div>
</template>

<script>
export default {
  name: 'CountView',
  data() {
    return {
      n: 1,
      num: 0,
    }
  },
  methods: {
    increment() {
      this.num += this.n
    },
    decrement() {
      this.num -= this.n
    },
    incrementOdd() {
      if (this.num % 2) {
        this.num += this.n
      }
    },
    incrementWait() {
      setTimeout(() => {
        this.num += this.n
      }, 500)
    }
  }
}
</script>

<style>

</style>